Cylinder crankcase assembly for dual crankshaft multi-cylinder engine

ABSTRACT

A multi-cylinder internal combustion engine which is assembled from two identical engines with an opposed piston-type arrangement and disposed symmetrically above one another, in which each of the two identical cylinder-crankcases are welded together from cast housing elements adjoined in a building-blocklike manner whereby the connection with each other of the two cylinder-crankcases takes place by way of flanged surfaces and the sides accessible from the top or bottom of the respective cylinder-crankcase is open for the installation of the crankshaft; the housing elements thereby include cross walls which are constructed for receiving the crankshaft main bearings and bifurcate Y-shaped in the direction toward the flanged surfaces for the other engine.

. United States Patent 91 Kubischiet al.

[75] Inventors: Hans-Joachim Kubisch; Richard Seifert; Walter Thorn, all of Friedrichshafen, Germany [73] Assignee: Motoren-und Turbinen-Union Friedrichshafen GmbII, Friedrichshafen, Germany [22] Filed: Dec. 28, 1971 [21] Appl. No.: 213,094

[30] Foreign Application Priority Data Jan. 9, 1971 Germany P 21 00 899.1

[52] US. Cl. 60/97 R, 123/52 A, 123/4l.35, 123/56 R, 123/195 R, 123/195 H, 123/DIG. 8 [51] Int. Cl. F0lk 23/00, F02b 75/24, F0lp 3/06 [58] Field of Search 123/56 A, 195 S, 123/52 A, DIG. 6, DIG. 7, DIG. 8, DIG. l, 195 H, 56 AB, 56 BB, 56 AA, 56 BA, 50 B; 60/97 R [5 6] References Cited UNITED STATES PATENTS 2,800,119 7/1957 Schmidl l23/41.35

[ Oct. 30, 1973 2,350,377 6/1944 Tjaorda [23/56 A 2,838,038 6/1958 Seifert 123/195 S 2,271,163 l/1942 Spencer .L 60/97 R 3,332,404 7/1967 Lovercheck... 123/52 A 1,457,115 5/1923 Leipert 123/D1G. 6 2,491,630 12/1949 Voorhies..... l23/DIG. 8 1,720,625 7/1929 Chorlton..... 123/195 H 2,634,586 4/1953 Pielstick 60/97 R Primary Examiner-Laurence M. Goodridge Assistant ExaminerDennis Toth AttorneyPaul M. Craig, Jr. et a1.

[57] ABSTRACT A multi-cylinder internal combustion engine which is assembled from two identical engines with an opposed piston-type arrangement and disposed symmetrically above one another, in which each of the two identical cylinder-crankcases are welded together from cast housing elements adjoined in a building-block-like manner whereby the connection with each other of the two cylinder-crankcases takes place by way of flanged surfaces and the sides accessible from the top or bottom of the respective cylinder-crankcase is open for the installation of the crankshaft; the housing elements thereby include cross walls which are constructed forreceiving the crankshaft main bearings and bifurcate Y-shaped in the direction toward the flanged surfaces for the other engine.

1 20 Claims, 4 Drawing Figures PATENTEDUBT 30 I975 SHEET 2 OF 2 FIG. 2

CYLINDER CRANKCASE ASSEMBLY FOR DUAL CRANKSHAFT MULTl-CYLINDER ENGINE The present invention relates to an internal combustion engine which is assembled from two engines symmetrically arranged one above the other with an opposed cylinder-type arrangement of the cylinders (boxer-type motor), and in which each of the two similar cylinder-crankcases is welded together from east housing elements joined adjacent one another in a buildingblock fashion, whereby the connection of the two cylindet-crankcases with one another takes place by way of flanged surfaces and the side of the respective cylindercrankcases accessible from the top or the bottom is constructed open for the installation of the crank shaft.

This type of constructionproduces a very compact internal combustion engine with high power density, whereby it is suited in particular for propulsion installations of ships for a high-speed propulsion and of highpower internal combustion engine locomotives.

Multi-cylinder internal combustion engines with an in-line or V-type'arrangement of the cylinders having welded-together cylinder-crankcases are known in the art. With this cylinder arrangement a sufficient rigidity of the cylinder-crankcase can be attained without special measures by the relatively high side and cross walls necessarily resulting therefrom. With opposed pistontype engines, conditioned by the cylinder arrangement, the side walls are low, interrupted by the cylinder bores and weakened thereby so that for the reinforcement of the cylinder-crankcase special measures must be taken.

The present invention is concerned with the task to develop a particularly rigid, welded cylinder-crankcase of so-called C-form with an opposed piston-type arrangement of the cylinders suited for each of the two engines of the aforementioned multi-cylinder internal combustion engine which also permits to interchange individual parts of the internal combustion engine installed into power propelled crafts.

The underlying problems are solved according to the present invention in that the housing elements include cross walls which are constructed for the installation of the crankshaft main bearings and are bifurcated Y- shaped in the direction toward the flanging surfaces for the other engine.

According to a further development of the present invention, the flanged surface is recessed channel-like over the entire length of the engine whereby the bifurcation of the cross walls extends from the two side walls of this channel toward the cylinders.

After the assembly of the cylinder-crankcases, the channels of both engines complement themselves into a hollow box-shaped bearer which imparts a particular bending rigidity to the cylinder-crankcases according to the present invention and forms in an advantageous manner an oil collecting channel for the oil sump missing with the upper engine.

According to a further feature of the present invention, bridge-like connecting elements are arranged on the open sides of the cylinder-crankcases open for the installation of the crankshafts, which connecting elements for the purpose of transmitting tensional forces, are provided at their connecting places at the cylindercrankcase with flat serrations whereby it is particularly advantageous to so construct these connecting elements that they exhibit the same expansions in operation as the cross walls of the cylinder-crankcases. A warping of the cylinder-crankcases due to non-uniform expansions is avoided thereby and the operating reliability of the engine is increased.

A problem resulted in connection with the piston cooling from the aimed-at identical construction of the engines and the symmetrical arrangement thereof one above the other. The cooling medium should be injected into the cooling channel of the pistons above the cylinder center plane and should again flow off therebelow as a result of gravitational forces. However, since the upper engine is mounted above the lower engine in a reserved position, the cooling medium would have had to flow in a reverse direction in the pistons of the upper engine.

This problem was solved according to the present invention in a simple manner in that the cross walls include on both sides of the crankshaft main bearings two eyes arranged symmetrically to the cylinder center plane and provided with bores, to which cooling medium for the pistons is supplied by way of channels in the cross walls from a supply line common for a cylinder row, which extends over the entire engine length and leads through the cross walls, and in that in each respective engine the resective upper bores are utilized for themounting of injection nozzles for the piston cooling system whereas the respective lower bores are closed tightly. It can thus be achieved by a simple measure during the assembly that in each of the two engines, depending on the respective use thereof as upper or lower engine, the correct flow of the cooling medium in the pistons is present and notwithstanding a far-reaching identity of the engines is achieved.

A further feature of the present invention resides in that each of the two engines includes a crankshaft assembled from two unitary parts, and in that the distance from the center of the connecting place of the partial crankshafts up to the center of the adjacent crankthro'ws corresponds to the center distance of adjacent cylinders.

The subdivision of the crankshaft enables a considerably facilitated handling during the machining and assembly, especially with engines having a large number of cylinders, and the disassembly is also greatly facilitated or even only made possible thereby in case of narrow spatial conditions as is often the case with ships propulsion installations.

A still further feature of the present invention resides in the arrangement of a housing section in the cylindercrankcase within the area of the connecting place of the two partial crankshafts which on the side of the housing is constructed like a normal cylinder section, however, which without the installation of individual parts is closed off by a blind cover in order to be able to utilize the same housing elements also at the connecting place of the two partial crankshafts, and in order to obtain thereby identical distances for the housing portions to be machined also over and beyond the connecting places of the two partial crankshafts.

Identical distances are a help for the rational manufacture since during the machining of the cylindercrankcase the worktool machine from one cylinder bore to the next can always be advanced by the sam distance.

The advantages achieved by the present invention consist especially in that the rational construction of an operationally reliable multi-cylinder internal combustion engine with welded together cylinder-crankcase is made possible which, notwithstanding high power, possesses a small structural volume, and which permits in the installed condition also under constricted spatial conditions a simple servicing and the exchange of nearly all individual parts up to the crankshafts.

Accordingly, it is an object of the present invention to provide a multi-cylinder internal combustion engine which avoids by simple means the aforementioned shortcomings and drawbacks encountered in the prior art.

Another object of the present invention resides in an opposite piston-type multi-cylinder internal combustion engine which is capable of producing high power and exhibits sufficient rigidity for its intended purposes.

A further object of the present invention resides in an opposite piston-type internal combustion engine which greatly facilitates servicing and interchange of the individual parts of the internal combustion engine, even when intalled into constricted spaces.

A still further object of the present invention resides in an internal combustion engine of the opposite cylinder type arrangement which not only possesses particular bending rigidity but also assures appropriate cooling of the pistons, even with two engines arranged one above the other.

Another object of the present invention resides in a high-power internal combustion engine in which two engines of opposed piston type of identical construction are arranged symmetrically one above the other and which excels by operational reliability as well as simplicity in manufacture assembly and disassembly.

These and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

FIG. 1 is a cross-sectional view of the assembled cylinder-crankcases of the two engines in accordance with the present invention, taken along line 11 of FIG. 2;

FIG. 2 is a longitudinal, cross-sectional view along the cylinder center plane and taken along line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view of a housing element taken along line 3-3 of FIG. 1; and

FIG. 4 is a partial, cross-sectional view taken along line IVIV of FIG. 1.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, two identical cylinder crankcases 11 and 11 (FIG. 1), which are welded together from cast housing elements 15, (FIGS. 2 to 4) arranged adjacent one another in a building-block-like manner, face on another by means of their flanged surfaces 12 and 12' (FIG. 1) along which they are threadably secured to one another. The housing elements l5, 15 (FIGS. 2 to 4) possess cross walls 13 which are constructed for the installation of the crankshaft main bearings 16 and 16' (FIG. 1) and which are provided with a Y-shaped bifurcation 14, 14 (FIG. 3 and FIG. 4) in the direction toward the flanged surfaces 12 and 12' for the other engine.

These bifurcations l4, 14 form respective arms of the Y with the straight portion of the cross wall which extend in the direction ofa main bearing plane perpendicular to the axis of rotation of the crankshaft being supported forming the leg of the Y. These bifurcations 14, 14' of the cross walls 13, 13' impart to the cylindercrankcase a very high rigidity.

The flanging surfaces 12 and 12 are recessed over the entire length of the engine into a type of channel 17 and 17' (FIG. 1), whereby a hollow box-shaped bearer reinforcing the cylinder-crankcase is formed. The bifurcation 14 of the cross walls 13 begins at the side walls 18 and 18 (FIG. I) of these channels 17 and 17' and extends toward the cylinders. Sprayed-off lubricating oil of the upper engine collects in the channels 17, 17' by way of the apertures 19 and is sucked-off from there into the oil tank. In the cylinder crankcase 11 which is utilized for te lower engine, the apertures 19' are tightly closed by means of rolled-in disks.

Bridge-like connecting elements 22 and 22 (FIG. 1) are arranged on the open sides 20 and 20' of the cylinder crankcases 11 and 11' which are open for the installation of the crankshafts 21 and 21. The connecting members 22 and 22' are provided with flat serrations at the cylinder-crankcase for the transmission of tensional forces at the connecting places 23 and 23' thereof, whereby the connecting members 22 and 22' are so constructed and dimensioned that they possess the same expansions during operation as the cross walls l3, 13' of the cylinder-crankcases 11 and 11'. A warping of the cylinder crankcases 11 and 11 as a result of unequal expansions is avoided thereby and the operational reliability of the engine is increased.

In order to assure with the symmetrical arrangement of the engines one above the other, as identical as possible a construction of the two engine housings, eyes 25, 25' and 26, 26' for the installation of the injection nozzles 31 (FIG. 1 and FIG. 3) for the piston cooling system are provided on the cross walls 13 on both sides of the crankshaft main bearings 16 symmetrically to the cylinder center plane (section 22 of FIG. 1) the eyes 25, 25' and 26, 26 are thereby provided with bores 29, 29' and 30, 30'. Cooling medium is supplied to these bores 29, 29' and 30, 30' for the purpose of cooling the pistons p(FIG. 1) by way of channels 27 (FIG. 3) in the cross walls 13 from a supply line 28 (FIGS. 2 and 3) extending through the cross walls 13, which is common to a respective cylinder row and extends over the entire length of the engine.

In each engine the respective upper bores, which in the illustrated embodiment are the bores 29 and 30', are equipped with spray nozzles 31 and the lower bores, i.e., the bores 30 and 29' are closed tightly by means of covers 32. It is assured thereby that with each of the two engines, depending on the respective use as upper or lower engine, the cooling medium is injected into the cooling channel of the pistons above the cylinder center plane 22 and is able to flow off therebelow due to gravitational forces.

The crankshafts 21 and 21' are assembled from two unitary parts 33 and 34 (FIG. 2), whereby the distance 35 from the center of the connecting place 36 of the partial crankshafts 33 and 34 up to the center of the adjacent crankthrows 38 and 39 corresponds to the center distance of adjacent cylinders.

The subdivision of the crankshaft permits a considerably more facilitated handling during the machining and assembly, especially in connection with engines having a large number of cylinders. Similarly, the disassembly under constricted spatial conditions, as is frequently the case in ships propulsion installations is greatly facilitated thereby or only made possible by such subdivision of the crankshafts.

Within the area of the connecting place 36 of the two partial crankshafts 33 and 34, the cylinder-crankcase ll has the same construction as with the cylinder sections 37 (FIG. 2), only with the difference that within the area of the connecting place 36 no individual parts are installed but instead the cylinder bores are closed off by means of blind covers. As a result thereof, the use of the same housing elements is made possible also within the area of the connecting place 36'of the partial crankshafts and one obtains also at 'thisplace identical spacings for the housing portions to be machined.

"Identical distances are a'facility for the rational manufacture since during the machining of the cylindercrankcase, the worktool machine can advance always by the same distance from one cylinder bore to the next.

While we have shown and described only one embodiment in accordance with the present invention,-it is understood that the same is not limited thereto but is susceptible to numerous changes and modifications as known to those skilled in the art and we, therefore, do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

We claim:

l. A multi-cylinder combustion engine arrangement comprising:

an upper engine unit including an upper cylindercrankcase for housing an upper crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said upper crankshaft, said upper cylinder-crankcase being openable from the top to accommodate insertion of said upper crankshaft, said upper cylinder-crankcase having downwardly facing flanged surface means extending along the bottom thereof, lower engine unit including a lower cylindercrankcase for housing a lower crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said lower crankshaft, said lower cylinder-crankcase being openable from the bottom to accommodate insertion of said lower crankshaft, said lower cylinder crankcase having upwardly facing flanged surface means extending along the top thereof,

each of said upper and lower cylinder-crankcases including a plurality of interconnected cast housing elements disposed adjacent one another in a building-block-like manner, each of said housing elements including cross-wall means for supporting respective crankshaft main bearings, each of said cross-wall means being of Y-shaped configuration with the leg of the Y disposed in a main bearing plane extending perpendicular to the axis of rota- I tion of the associated crankshaft and the arms of the Y extending to the associated flanged surface means in such a manner that the arms intersect flanged surface means at positions spaced longitu dinally from one another at opposite sides of said main bearing plane,

and connecting means for connecting said upper and lower engine units to one another along respective abutting surfaces of the respective flanged surface means.

2. An arrangement according to claim 1, characterized in that the flanged surface means are recessed channel-like substantially over the entire length of the engine and the arms of the Y-shaped cross wall means extend from side walls of the channel in a direction toward respective piston accommodating spaces in the respective cylinder-crankcases.

3. An arrangement according to claim 2, characterized in that the channel-like recesses of said flanged surface means of the two engines together form a hollow box-shaped bearer means which imparts a particular bending rigidity to the assembled cylindercrankcase means.

4. An arrangement according to claim 3, characterized in that the hollow box-shaped bearer means forms a lubricant collecting channel for the upper engine unit.

5. An arrangement according to claim 4, characterized in that bridge-like connecting members are arranged on the respective side of each of the respective cylinder-crankcase which is open for the installation of the respective associated crankshaft, and in that the bridge-like connecting members are provided with serrations for the transmission of tensional forces at their respective connecting places with the cylindercrankcases, said connecting members being so constructed that they have substantially the same expansions as the cross wall means of the cylinder-crankcase means during engine operation.

6. An arrangement according to claim 5, characterized in that each of the engine units includes a crankshaft assembled from two unitary parts, and in that the distance from the center of the connecting place of the partial crankshafts to the center of adjacent crankthrows corresponds to the distance between the centers of adjacent piston accommodating spaces in said respective cylinder crankcase.

7. An arrangement according to claim 6, characterized by a housing section in each of the respective cylinder-crankcases within the area of the connection of the two partial crankshafts which is constructed like another cylinder section but without the installation of individual piston and cylinder parts and closed by a cover in order to obtain identical distances for the housing portions-to be machined also over the connecting places of the two partial crankshafts.

'8. An arrangement according to claim 1, characterized in that bridge-like connecting members are arranged on the respective side of each of the respective cylinder-crankcase which is open for the installation of the respective associated crankshaft, and in that the bridge-like connecting members are provided with serrations for the transmission of tensional forces at their respective connecting places with the cylindercrankcases, said connecting members being so constructed that they have substantially the same expansions as the cross wall means of the cylinder-crankcase means during engine operation.

9. An arrangement according to claim 1, characterized in that each of the engine units includes a crankshaft assembled from two unitary parts, and in that the distance from the center of the connecting place of the partial crankshafts to the center of adjacent crankthrows corresponds to the distance between the centers of adjacent piston accommodating spaces in said respective cylinder-crankcases.

10. An arrangement according to claim 9, characterized by a housing section in each of the respective cylinder-crankcases within the area of the connection of the two partial crankshafts which is constructed like another cylinder section but without the installation of individual piston and cylinder parts and closed by a cover in order to obtain identical distances for the housing portions to be machined also over the connecting places of the two partial crankshafts.

11. An arrangement according to claim 9, characterized in that bridge-like connecting members are arranged on the respective side of each of the respective cylinder-crankcase which is open for the installation of the respective associated crankshaft, and in that the bridge-like connecting members are provided with serrations for the transmission of tensional forces at their respective connecting places with the cylindercrankcases, said connecting members being so constructed that they have substantially the same expansions as the cross wall means of the cylinder-crankcase means during engine operation.

12. An arrangement according to claim 5, further comprising: coolant supply means for conducting coolant to respective piston accommodating spaces in said cylinder-crankcases, said coolant supply means including: a pair of bores formed in each of said cross-wall means for each respective piston accommodating space i in each of said cylinder-crankcases, each pair of bores being spaced an equal distance from a vertically extending center plane through the axes of rotation of the crankshafts, the bores of each pair being disposed at opposite sides of and equidistantly from a horizontal crankshaft plane through the axis of rotation of the associated crankshaft, the crankshaft planes of said upper and lower engine units being spaced an equal distance from a horizontal flanged surface plane through said abutting surface of the respective flanged surface means, coolant line means leading to each of said bores with the bores of a pair being serially arranged with respect to flow through said coolant line means, detachable closing means for closing the lowermost bore of each pair of bores, and detachable spray nozzle means in the uppermost bore of each pair of bores for spraying coolant from said line means to the associated piston accommodating space, said closing means and spray nozzle means being interchangeably mountable in each bore of said pair of bores such that a cylindercrankcase can be used as either an upper or lower cylinder-crankcase with an unchanged orientation of said spray nozzles.

13. An arrangement according to claim 1, further comprising: coolant supply means for conducting coolant to respective piston accommodating spaces in said cylinder-crankcases, said coolant supply means including: a pair of bores formed in each of said cross-wall means for each respective piston accommodating space in each of said cylinder-crankcases, each pair of bores being spaced an equal distance from a vertically extending center plane through the axes of rotation of the crankshafts, the bores of each pair being disposed at opposite sides of and equidistantly from a horizontal crankshaft plane through the axis of rotation of the associated crankshaft, the crankshaft planes of said upper and lower engine units being spaced an equal distance from a horizontal flanged surface plane through said abutting surfaces of the respective flanged surface means, coolant line means leading to each of said bores with the bores of a pair being serially arranged with respect to flow through said coolant line means, detachable closing means for closing the lowermost bore of each pair of bores, and detachable spray nozzle means in the uppermost bore of each pair of bores for spraying coolant from said line means to the associated piston accommodating space, said closing means and spray nozzle means being interchangeably mountable in each bore of said pair of bores such that a cylindercrankcase can be used as either an upper or lower cylinder-crankcase with an unchanged orientation of said spray nozzles.

14. An arrangement according to claim 10, further comprising: coolant supply means for conducting coolant to respective piston accommodating spaces in said cylinder-crankcases, said coolant supply means including: a pair of bores formed in each of said cross-wall means for each respective piston accommodating space in each of said cylinder-crankcases, each pair of bores being spaced an equal distance from a vertically extending center plane through the axes of rotation of the crankshafts, the bores of each pair being disposed at opposite sides of and equidistantly from a horizontal crankshaft plane through the axis of rotation of the associated crankshaft, the crankshaft planes of said upper and lower engine units being spaced an equal distance from a horizontal flanged surface plane through said abutting surfaces of the respective flanged surface means, coolant line means leading to each of said bores with the bores of a pair being serially arranged with respect to flow through said coolant line means, detachable closing means for closing the lowermost bore of each pair of bores, and detachable spray nozzle means in the uppermost bore of each pair of bores for spraying coolant from said line means to the associated piston accommodating space, said closing means and spray nozzle means being interchangeably mountable in each bore of said pair of bores such that a cylindercrankcase can be used as either an upper or lower cylinder-crankcase with an unchanged orientation of said spray nozzles.

15. An arrangement according to claim 1, wherein said cast housing elements of the respective cylindercrankcases are interconnected by welding.

16. A multi-cylinder internal combustion engine arrangement comprising:

an upper engine unit including an upper cylindercrankcase for housing an upper crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said upper crankshaft, said upper cylinder-crankcase being openable from the top to accommodate insertion of said upper crankshaft, said upper cylinder-crankcase having downwardly facing flanged surface means extending along the bottom thereof, lower engine unit including a lower cylindercrankcase for housing a lower crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said lower crankshaft, said lower cylinder-crankcase being openable from the bottom to accommodate insertion of said lower crankshaft, said lower cylinder crankcase having upwardly facing flanged surface means extending along the top thereof,

each of said upper and lower cylinder-crankcases including a plurality of cross-wall means for supporting respective crankshaft main bearings, connecting means for connecting said upper and lower engine units to one another along respective abutting surfaces of their respective flanged surface means,

and coolant supply means for conducting coolant to respective piston accommodating spaces in said cylinder-crankcases, said coolant supply means including: a pair of bores formed in each of said cross-wall means for each respective piston accommodating space in each of said cylindercrankcases, each pair of bores being spaced an equal distance from a vertically extending center plane through the axes of rotation of the crankshafts, the bores of each pair being disposed at opposite sides of and equidistantly from a horizontal crankshaft plane through the axis of rotation of the associated crankshaft, the crankshaft planes of said upper and lower engine units being spaced an equal distance from a horizontal flanged surface plane through said abutting surfaces of the respective flanged surface means, coolant line means leading to each of said bores with the bores of a pair being serially arranged with respect to flow through said coolant line means, detachable closing means for closing the lowermost bore of each pair of bores, and detachable spray nozzle means in the uppermost bore of each pair of bores for spraying coolant from said line means to the associated piston accommodating space, said closing means and spray nozzle means being interchangeably mountable in each bore of said pair of bores such that a cylinder-crankcase can be used as either an upper or lower cylinder-crankcase with an unchanged orientation of said spray nozzles.

17. An arrangement according to claim 16, wherein each of said upper and lower cylinder-crankcases are formed from a plurality of interconnected cast housing elements disposed adjacent one another in a buildingblock-like manner, each of said housing elements including one of said respective cross-wall means.

18. An arrangement according to claim 17, wherein said cast housing elements of the respective cylindercrankcases are interconnected by welding.

19. An arrangement according to claim 16, wherein each of the engine units includes a crankshaft assembled from two unitary parts, the distance from the center of the connecting place of the partial crankshafts to the center of adjacent crankthrows corresponding to the distance between the centers of adjacent piston accommodating spaces in said respective cylindercrankcases, and wherein each of the respective cylinder-crankcases is provided by a housing section within the area of the connection of the two partial crankshafts which is constructed similar to adjacent cylinder sections but without the installation of individual piston and cylinder parts and being closed by a cover in order to obtain identical distances for the housing portions to be machined also over the connecting places of the two partial crankshafts.

20. A multi-cylinder internal combustion engine arrangement comprising:

an upper engine unit including an upper cylindercrankcase for housing an upper crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said upper crankshaft, said upper cylinder-crankcase being openable from the top to accommodate insertion of said upper crankshaft, said upper cylinder-crankcase having downwardly facing flanged surface means extending along the bottom thereof, a lower engine unit including a lower cylindercrankcase for housing a lower crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said lower crankshaft, said lower cylinder-crankcase being openable from the bottom to accommodate insertion of said lower crankshaft, said lower cylinder crankcase having upwardly facing flanged surface means extending along the top thereof, and connecting means for connecting said upper and lower engine units to-one another along respective abutting surfaces of the respective flanged surface means, wherein each of the engine units includes a crankshaft assembled from two unitary parts, the distance from the center of the connecting place of the partial crankshafts to the center of adjacent crankthrows corresponding to the distance between the centers of adjacent piston accommodating spaces in said respective cylinder-crankcases, and wherein each of the respective cylindercrankcases is provided by a housing section within the area of the connection of the two partial crankshafts which is constructed similar to adjacent cylinder sections but without the installation of individual piston and cylinder parts and being closed by a cover in order to obtain identical distances for the housing portions to be machined also over the connecting places of the two partial crankshafts. 

1. A multi-cylinder combustion engine arrangement comprising: an upper engine unit including an upper cylinder-crankcase for housing an upper crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said upper crankshaft, said upper cylinder-crankcase being openable from the top to accommodate insertion of said upper crankshaft, said upper cylinder-crankcase having downwardly facing flanged surface means extending along the bottom thereof, a lower engine unit including a lower cylinder-crankcase for housing a lower crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said lower crankshaft, said lower cylinder-crankcase being openable from the bottom to accommodate insertion of said lower crankshaft, said lower cylinder crankcase having upwardly facing flanged surface means extending along the top thereof, each of said upper and lower cylinder-crankcases including a plurality of interconnected cast housing elements disposed adjacent one another in a building-block-like manner, each of said housing elements including cross-wall means for supporting respective crankshaft main bearings, each of said cross-wall means being of Y-shaped configuration with the leg of the Y disposed in a main bearing plane extending perpendicular to the axis of rotation of the associated crankshaft and the arms of the Y extending to the associated flanged surface means in such a manner that the arms intersect said flanged surface means at positions spaced longitudinally from one another at opposite sides of said main bearing plane, and connecting means for connecting said upper and lower engine units to one another along respective abutting surfaces of the respective flanged surface means.
 2. An arrangement according to claim 1, characterized in that the flanged surface means are recessed channel-like substantially over the entire length of the engine and the arms of the Y-shaped cross wall means extend from side walls of the channel in a direction toward respective piston accommodating spaces in the respective cylinder-crankcases.
 3. An arrangement according to claim 2, characterized in that the channel-like recesses of said flanged surface means of the two engines together form a hollow box-shaped bearer means which imparts a particular bending rigidity to the assembled cylinder-crankcase means.
 4. An arrangement according to claim 3, characterized in that the hollow box-shaped bearer means forms a lubricant collecting channel for the upper engine unit.
 5. An arrangement according to claim 4, characterized in that bridge-like connecting members are arranged on the respective side of each of the respective cylinder-crankcase which is open for the installation of the respective associated crankshaft, and in that the bridge-like connecting members are provided with serrations for the trAnsmission of tensional forces at their respective connecting places with the cylinder-crankcases, said connecting members being so constructed that they have substantially the same expansions as the cross wall means of the cylinder-crankcase means during engine operation.
 6. An arrangement according to claim 5, characterized in that each of the engine units includes a crankshaft assembled from two unitary parts, and in that the distance from the center of the connecting place of the partial crankshafts to the center of adjacent crankthrows corresponds to the distance between the centers of adjacent piston accommodating spaces in said respective cylinder crankcase.
 7. An arrangement according to claim 6, characterized by a housing section in each of the respective cylinder-crankcases within the area of the connection of the two partial crankshafts which is constructed like another cylinder section but without the installation of individual piston and cylinder parts and closed by a cover in order to obtain identical distances for the housing portions to be machined also over the connecting places of the two partial crankshafts.
 8. An arrangement according to claim 1, characterized in that bridge-like connecting members are arranged on the respective side of each of the respective cylinder-crankcase which is open for the installation of the respective associated crankshaft, and in that the bridge-like connecting members are provided with serrations for the transmission of tensional forces at their respective connecting places with the cylinder-crankcases, said connecting members being so constructed that they have substantially the same expansions as the cross wall means of the cylinder-crankcase means during engine operation.
 9. An arrangement according to claim 1, characterized in that each of the engine units includes a crankshaft assembled from two unitary parts, and in that the distance from the center of the connecting place of the partial crankshafts to the center of adjacent crankthrows corresponds to the distance between the centers of adjacent piston accommodating spaces in said respective cylinder-crankcases.
 10. An arrangement according to claim 9, characterized by a housing section in each of the respective cylinder-crankcases within the area of the connection of the two partial crankshafts which is constructed like another cylinder section but without the installation of individual piston and cylinder parts and closed by a cover in order to obtain identical distances for the housing portions to be machined also over the connecting places of the two partial crankshafts.
 11. An arrangement according to claim 9, characterized in that bridge-like connecting members are arranged on the respective side of each of the respective cylinder-crankcase which is open for the installation of the respective associated crankshaft, and in that the bridge-like connecting members are provided with serrations for the transmission of tensional forces at their respective connecting places with the cylinder-crankcases, said connecting members being so constructed that they have substantially the same expansions as the cross wall means of the cylinder-crankcase means during engine operation.
 12. An arrangement according to claim 5, further comprising: coolant supply means for conducting coolant to respective piston accommodating spaces in said cylinder-crankcases, said coolant supply means including: a pair of bores formed in each of said cross-wall means for each respective piston accommodating space in each of said cylinder-crankcases, each pair of bores being spaced an equal distance from a vertically extending center plane through the axes of rotation of the crankshafts, the bores of each pair being disposed at opposite sides of and equidistantly from a horizontal crankshaft plane through the axis of rotation of the associated crankshaft, the crankshaft planes of said upper and lower engine units being spaced an equal distance from a horizontal flanged surface pLane through said abutting surface of the respective flanged surface means, coolant line means leading to each of said bores with the bores of a pair being serially arranged with respect to flow through said coolant line means, detachable closing means for closing the lowermost bore of each pair of bores, and detachable spray nozzle means in the uppermost bore of each pair of bores for spraying coolant from said line means to the associated piston accommodating space, said closing means and spray nozzle means being interchangeably mountable in each bore of said pair of bores such that a cylinder-crankcase can be used as either an upper or lower cylinder-crankcase with an unchanged orientation of said spray nozzles.
 13. An arrangement according to claim 1, further comprising: coolant supply means for conducting coolant to respective piston accommodating spaces in said cylinder-crankcases, said coolant supply means including: a pair of bores formed in each of said cross-wall means for each respective piston accommodating space in each of said cylinder-crankcases, each pair of bores being spaced an equal distance from a vertically extending center plane through the axes of rotation of the crankshafts, the bores of each pair being disposed at opposite sides of and equidistantly from a horizontal crankshaft plane through the axis of rotation of the associated crankshaft, the crankshaft planes of said upper and lower engine units being spaced an equal distance from a horizontal flanged surface plane through said abutting surfaces of the respective flanged surface means, coolant line means leading to each of said bores with the bores of a pair being serially arranged with respect to flow through said coolant line means, detachable closing means for closing the lowermost bore of each pair of bores, and detachable spray nozzle means in the uppermost bore of each pair of bores for spraying coolant from said line means to the associated piston accommodating space, said closing means and spray nozzle means being interchangeably mountable in each bore of said pair of bores such that a cylinder-crankcase can be used as either an upper or lower cylinder-crankcase with an unchanged orientation of said spray nozzles.
 14. An arrangement according to claim 10, further comprising: coolant supply means for conducting coolant to respective piston accommodating spaces in said cylinder-crankcases, said coolant supply means including: a pair of bores formed in each of said cross-wall means for each respective piston accommodating space in each of said cylinder-crankcases, each pair of bores being spaced an equal distance from a vertically extending center plane through the axes of rotation of the crankshafts, the bores of each pair being disposed at opposite sides of and equidistantly from a horizontal crankshaft plane through the axis of rotation of the associated crankshaft, the crankshaft planes of said upper and lower engine units being spaced an equal distance from a horizontal flanged surface plane through said abutting surfaces of the respective flanged surface means, coolant line means leading to each of said bores with the bores of a pair being serially arranged with respect to flow through said coolant line means, detachable closing means for closing the lowermost bore of each pair of bores, and detachable spray nozzle means in the uppermost bore of each pair of bores for spraying coolant from said line means to the associated piston accommodating space, said closing means and spray nozzle means being interchangeably mountable in each bore of said pair of bores such that a cylinder-crankcase can be used as either an upper or lower cylinder-crankcase with an unchanged orientation of said spray nozzles.
 15. An arrangement according to claim 1, wherein said cast housing elements of the respective cylinder-crankcases are interconnected by welding.
 16. A multi-cylinder internal combustion engine arrangement comprising: an upper engine unit including an upper cylinder-crankcase For housing an upper crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said upper crankshaft, said upper cylinder-crankcase being openable from the top to accommodate insertion of said upper crankshaft, said upper cylinder-crankcase having downwardly facing flanged surface means extending along the bottom thereof, a lower engine unit including a lower cylinder-crankcase for housing a lower crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said lower crankshaft, said lower cylinder-crankcase being openable from the bottom to accommodate insertion of said lower crankshaft, said lower cylinder crankcase having upwardly facing flanged surface means extending along the top thereof, each of said upper and lower cylinder-crankcases including a plurality of cross-wall means for supporting respective crankshaft main bearings, connecting means for connecting said upper and lower engine units to one another along respective abutting surfaces of their respective flanged surface means, and coolant supply means for conducting coolant to respective piston accommodating spaces in said cylinder-crankcases, said coolant supply means including: a pair of bores formed in each of said cross-wall means for each respective piston accommodating space in each of said cylinder-crankcases, each pair of bores being spaced an equal distance from a vertically extending center plane through the axes of rotation of the crankshafts, the bores of each pair being disposed at opposite sides of and equidistantly from a horizontal crankshaft plane through the axis of rotation of the associated crankshaft, the crankshaft planes of said upper and lower engine units being spaced an equal distance from a horizontal flanged surface plane through said abutting surfaces of the respective flanged surface means, coolant line means leading to each of said bores with the bores of a pair being serially arranged with respect to flow through said coolant line means, detachable closing means for closing the lowermost bore of each pair of bores, and detachable spray nozzle means in the uppermost bore of each pair of bores for spraying coolant from said line means to the associated piston accommodating space, said closing means and spray nozzle means being interchangeably mountable in each bore of said pair of bores such that a cylinder-crankcase can be used as either an upper or lower cylinder-crankcase with an unchanged orientation of said spray nozzles.
 17. An arrangement according to claim 16, wherein each of said upper and lower cylinder-crankcases are formed from a plurality of interconnected cast housing elements disposed adjacent one another in a building-block-like manner, each of said housing elements including one of said respective cross-wall means.
 18. An arrangement according to claim 17, wherein said cast housing elements of the respective cylinder-crankcases are interconnected by welding.
 19. An arrangement according to claim 16, wherein each of the engine units includes a crankshaft assembled from two unitary parts, the distance from the center of the connecting place of the partial crankshafts to the center of adjacent crankthrows corresponding to the distance between the centers of adjacent piston accommodating spaces in said respective cylinder-crankcases, and wherein each of the respective cylinder-crankcases is provided by a housing section within the area of the connection of the two partial crankshafts which is constructed similar to adjacent cylinder sections but without the installation of individual piston and cylinder parts and being closed by a cover in order to obtain identical distances for the housing portions to be machined also over the connecting places of the two partial crankshafts.
 20. A multi-cylinder internal combustion engine arrangement comprising: an upper engine unit including an upper cylinder-crankcase for housing an upper crankshaft And a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said upper crankshaft, said upper cylinder-crankcase being openable from the top to accommodate insertion of said upper crankshaft, said upper cylinder-crankcase having downwardly facing flanged surface means extending along the bottom thereof, a lower engine unit including a lower cylinder-crankcase for housing a lower crankshaft and a plurality of reciprocable oppositely extending pistons operatively drivingly connectible with said lower crankshaft, said lower cylinder-crankcase being openable from the bottom to accommodate insertion of said lower crankshaft, said lower cylinder crankcase having upwardly facing flanged surface means extending along the top thereof, and connecting means for connecting said upper and lower engine units to one another along respective abutting surfaces of the respective flanged surface means, wherein each of the engine units includes a crank-shaft assembled from two unitary parts, the distance from the center of the connecting place of the partial crankshafts to the center of adjacent crankthrows corresponding to the distance between the centers of adjacent piston accommodating spaces in said respective cylinder-crankcases, and wherein each of the respective cylinder-crankcases is provided by a housing section within the area of the connection of the two partial crankshafts which is constructed similar to adjacent cylinder sections but without the installation of individual piston and cylinder parts and being closed by a cover in order to obtain identical distances for the housing portions to be machined also over the connecting places of the two partial crankshafts. 